Question about Sealing a Pond

I don't have access to solid animal waste for a gley pond liners, and I would be very reluctant to use it if I did.

Will alternating thin layers of dead leaves and clay slurry work to seal a pond in heavy clay soil?  If so, how many inches thick should it be?  There are tree roots being exposed by my excavation for the pond.  Small roots are being pruned, but there are large roots that will be remaining in place.  Should I dig under or just line oner exposed large roots?

I am thinking of a light coat of clay slurry, add layer of leaves, pack once the clay is tacky but not dry, and repeating several times.  Once thick enough, add a final layer of clay slurry, wait until tacky but not dry and pack the last layer of clay down.  Then soil where I want pond plants and pea gravel the rest of the bed.  

What is the subsoil?
Is it mostly clay or stones/sand?

Drew Moffatt wrote:What is the subsoil?
Is it mostly clay or stones/sand?

Very heavy clay soil.  Even the organic topsoil is heavy clay soil.

When we build ponds here in clay country we make sure the entire inside is lined with clay then track roll it multiple times with the excavator.
The old way was to run a thousand ewes over it a few times and their feet would pack down and seal the clay lining.
Not sure how big your pond is or what you have in hand?

Drew Moffatt wrote:When we build ponds here in clay country we make sure the entire inside is lined with clay then track roll it multiple times with the excavator.
The old way was to run a thousand ewes over it a few times and their feet would pack down and seal the clay lining.
Not sure how big your pond is or what you have in hand?

Just me and a 3rd grader, pond is small enough to fit in a suburban back yard, maybe a couple hundred square feet and a couple feet depth, max.

Lets say it is a 25ft by 25ft pond (625sqft).
I would use grass a grass and clay slurry, and then keep it misted for a couple week. Once it seals never let the water level in the pond go down.

S Bengi wrote:Lets say it is a 25ft by 25ft pond (625sqft).
I would use grass a grass and clay slurry, and then keep it misted for a couple week. Once it seals never let the water level in the pond go down.

Thank you both for your help.

I have plenty of fallen leaves, but no cut grass or funds to get grass or hay.  Is there a reason that leaves would not work as a substitute?

Or should I wait until spring and lawn mowing season when we will have cut grass?

Drew Moffatt wrote:The old way was to run a thousand ewes over it a few times and their feet would pack down and seal the clay lining.

The Kentucky version was letting pigs wallow in it for a season.

Me, a 3rd grader who might be of a little bit of help and three cats who will be of no help whatsoever.

I will put in the sweat equity to do this.  At this point it is down to whether I add fallen leaves and start in December or wait and use grass clippings in April or May.  If leaves will work, I am impatient and want to start soon.  If they won't, I need to curb my impatience and wait until our lawn needs to be mowed.  

I think the leaves can work, but if you can get something in there along with them that has lots of nitrogen they will work better. What you're trying to get is a sort of anaerobic composting process which jumps-starts the formation of cryptobiotic slime underwater. That's why grass clippings work so well...they have a low C:N ration (which is why they heat up quickly if you pile them).

Are you ruling out manure because you don't have access to any, or because of other reasons like ick factor? What about coffee grounds? Shouldn't take too much for a small pond, as the leaves will be provide the bulk.

Ruth Meyers wrote:

Drew Moffatt wrote:The old way was to run a thousand ewes over it a few times and their feet would pack down and seal the clay lining.

The Kentucky version was letting pigs wallow in it for a season.

So was the Ozark version :)

Phil Stevens wrote:I think the leaves can work, but if you can get something in there along with them that has lots of nitrogen they will work better. What you're trying to get is a sort of anaerobic composting process which jumps-starts the formation of cryptobiotic slime underwater. That's why grass clippings work so well...they have a low C:N ration (which is why they heat up quickly if you pile them).

Are you ruling out manure because you don't have access to any, or because of other reasons like ick factor? What about coffee grounds? Shouldn't take too much for a small pond, as the leaves will be provide the bulk.

Both lack of access/funds to buy and ick factor.

My in-laws go through a lot of coffee.  I could try asking at coffee shops or the University.  Personally, I refer to coffee as “the stinky stuff”.  I never acquire a taste for it.  My spouse will drink it socially, but doesn’t enjoy it.

When I dug my pond the earth was mostly clay mixed with stones and gravel, with horizontal seams of sandy gravel. I didn't have enough time with the excavator to pull away the spoils but that worked out in my favor. The first rains drained away through the lowest sandy gravel seam but it got progressively better as the rains washed more clay into the bottom of the pond which plugged off the seams.